Microfabricated Ion-Selective Filter for Desalination
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Solution Overview
Problem
Current desalination technologies, such as reverse osmosis and thermal distillation, are energy-intensive and prone to corrosion and scaling, while ion concentration polarization methods lack scalability and throughput for large-scale water purification.
Innovation Solution
A microfabricated filtration membrane with a substrate of micropores or nanopores, an ion-selective layer, and conductive layers configured to apply voltage across the pores, utilizing ion concentration polarization for efficient separation and desalination, scalable through microfabrication and micromachining processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional reverse osmosis or thermal distillation is used for desalination, then water purification is achieved, but energy consumption is high and corrosion/scaling problems occur
Solution Approach 1:
The patent replaces the mechanical pressure-driven reverse osmosis system with an electric field-driven ion concentration polarization system. The conductive layers apply voltage across the micropores to create ion depletion zones that selectively filter salt ions without requiring high pressure, thereby reducing energy consumption while maintaining purification effectiveness
Solution Approach 2:
The patent changes the operating parameters from high pressure (RO) or high temperature (thermal distillation) to controlled voltage application. By adjusting the voltage applied across the conductive layers, the system achieves ion separation at lower energy input, avoiding the energy-intensive conditions of conventional methods
2Use of energy by moving object
If microfluidic chip-based ion concentration polarization is used, then energy efficiency is improved, but throughput is insufficient for large-scale application
Solution Approach 1:
The patent segments the filtration function into multiple parallel micropores (1-100 μm) arranged in a membrane structure. Each micropore acts as an independent filtration channel with its own ion depletion zone, allowing simultaneous processing of multiple fluid streams. This parallel architecture enables scaling from microfluidic to large-scale throughput while maintaining the energy-efficient ICP mechanism
Solution Approach 2:
The patent transitions from two-dimensional microfluidic channel surfaces to three-dimensional volumetric processing through the membrane structure. The conductive layers are positioned on both sides of the membrane with micropores extending through the thickness, creating ion depletion zones that utilize the third dimension (membrane thickness) to enhance filtration capacity and throughput
3Reliability
If membrane-based reverse osmosis is used, then filtration is effective, but membrane fouling and scaling occur
Solution Approach 1:
The patent replaces the physical membrane barrier of RO with an electric field-based ion depletion mechanism. Ions are removed from the solution through electrostatic repulsion in the depletion zones formed at the micropore entrances, rather than being physically blocked by a membrane. This eliminates the fouling and scaling problems that plague conventional RO membranes
Solution Approach 2:
The patent introduces conductive layers as intermediaries that generate the electric field necessary for ion concentration polarization. These conductive layers apply voltage to create the ion depletion zones without requiring direct contact between the membrane and the feed solution, reducing the tendency for fouling and scaling on the filtration surface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high-throughput filtration and desalination with reduced energy consumption and clogging, enabling efficient purification of seawater and other fluids, and is applicable for both water treatment and biomolecule separation.
Implementation Method 1
A recently developed desalination method based on ion concentration polarization (ICP) offers an interesting alternative to the membrane-based approach to desalination
Data Source
AI summary
A microfabricated filtration membrane including a substrate containing a plurality of micropores, an ion-selective layer, and at least two conductive layers configured to apply a voltage across the micropores. The geometry of the conductive layers matches the geometry of the micropores (or nanopores).